Recommended ground for 2nd batt in trunk ('07 monte carlo)

[jdcranke07]

I'm a DIY-er type with car audio and i've found two different methods for grounding out the 2nd batt in my trunk.

first: i heard that you need to ground it out on the alt itself

second: i heard that you just need to find a good ground spot in the trunk

dilemma: i'm not exactly sure what would be considered a good ground in a 2007 monte carlo's trunk

current set-up: front batt wired to alt and grounded normally, trunk batt wired to alt and grounded to trunk wall behind passenger tail light (recommendation of installer of alt at local shop)

[Mobileaudio25]

If you feel comfortable drilling through the trunk floor, ground directly to the frame/subframe. If not find a solid metal spot in the trunk and ground it there. Make SURE paint is cleaned with a wire bush or file so that the metal is shines and no paint at all. Then lock it down and apply paint over it to ensure no rust (for durability)

[newb]

you shouldnt have a problem with it grounded where it is

[Fosgatefeind]

the floor of your trunk is directly on top of the frame i drilled through to the frame and did it right there. i have the same car

[jdcranke07]

OK, but now here is the issue I've had since I had the 270 amp H/O alt put in; it has white noise. It is a single continuous ring that follows the RPM of my engine. I had to send alt back to manufacturer for faulty volt regulator after first installation. I've had no power issues and no short or anything. However, that white noise bugs the living hell out of me and I know it can be any of my connections, especially grounds.